Space-charge limiting currents in magnetically focused intense relativistic beams with an ion channel

The intense relativistic beam propagation through the drift tube filled with background plasma is investigated. The self-consistent differential equations, which describe the laminar-flow equilibria state in magnetically focused relativistic beams with an ion channel, are presented. By solving these equations using the Runge-Kutta method, the azimuthal velocity, the axial velocity, and the electron beam density, which are functions of radial position, can be calculated. Then the space-charge limiting current and the externally applied magnetic field can be obtained for solid beams and hollow beams. In the case of plasma fill, the axial velocity of the laminar flow is a nonuniform radial profile. The simulated results show that the background plasma can increase the space-charge limiting current, reduce the externally applied magnetic field, and improve the electron beam propagation through the drift tube. (c) 2006 American Institute of Physics.